Aromatic polycarbonates are well known polymers having excellent properties of impact resistance, toughness, heat resistance, and dimensional strength. However, these polycarbonates generally exhibit relatively poor resistance to solvents. Resistance to organic solvents, particularly those having a high aromatic content, is not exceptional and may be upgraded significantly. Of particular concern is the relatively poor resistance of aromatic polycarbonates to basic solvents such as those containing hydroxyl groups, basic alcohols, and amines. Basic substances are known to attack the carbonate bond thereby forming oligomers out of the polycarbonate resin with a concomitant decrease in such properties as impact strength.
The admixing of aromatic polycarbonates with other polymers is generally carried out in order to upgrade certain properties of polycarbonates. Because of their great strength to weight ratio, as well as upgrading of other properties, aromatic polycarbonate admixtures have extended the application of aromatic polycarbonates to many potential fields, particularly the automotive field. Various upgrading of certain properties must be done to provide a polycarbonate composition suitable for various specific applications. For example, a part made for use in or near engine compartments of an automotive vehicle should maintain good properties at high temperatures. Exposure to certain chemicals such as gasoline can be very significant for a bumper made of polycarbonate. Often, however, the improvement of one property by blending the polycarbonate with another plastic resin may not result in the improvement of another property, or may actually lower or adversely affect other properties. Futhermore, the blending of polycarbonate with certain other resins can bring about incompatibility problems as shown by surface delamination, poor weld line strength, excessive stress cracking or crazing, and the like.
It is an object of the instant invention to provide polycarbonate compositions exhibiting improved resistance to solvents while simultaneously exhibiting good compatability of the individual components of these compositions.